Expression Of CD98in Mice With Experimental Inflammatory Bowel Disease

Backgrounds and ObjectivesInflammatory bowel diseases(IBD) includes ulcerative colitis(UC) and Crohn’s disease(CD). At present, the etiology and pathogenesis of IBD is not very clear. IBD is common in western countries, but in recent years the incidence of IBD also increased year by year in our country. Now,most scholars consider that the etiology and pathogenesis of IBD includes environmental factors,genetic factors,infection and immune factors,and the immune factors play a key role in the pathogenesis of IBD. Beta1integrin is a subgroup of integrin, mainly mediate the adhesion between cells and extracellular matrix components.In recent years,we found that CD98can through a variety of mechanisms to adjust the expression and clustering of betal integrin, and then affects cell adhesion, polarization, etc,so that it promotes the inflammation process and perpetuates intestinal inflammation.CD98has amino acid transport function,and also can promote the proliferation and cell fusion, etc.At present, the domestic research relating CD98with IBD is little.Through establishing a IBD animal model, observing the disease activity situation of mice, and the colonic histology changes, detecting the expression level of CD98in peripheral blood and colon tissues of this animal model. And that by making an intervention on the model group, we aimed to research the role of CD98in the pathogenesis of IBD.MethodsSPF male BALb/c mice were randomly divided into four groups,each group consisting of twelve mice. normal control group:mice were given an unrestricted diet, saline group:mice were put in a fasted state for twenty-four hours,then given unrestricted water after having received a100μl saline enema and given an unrestricted diet. On the eighth day and the fifteenth day, this operating was repeated.50%ethanol group:mice were given50%100μl ethanol solution enema, other steps were the same to the saline group. TNBS+50%ethanol group:mice were put in a fasted state for twenty-four hours,then given unrestricted water.Mice were given2.0mg TNBS/50%ethanol100μl enema on the1st day,2.5mg TNBS/50%ethanol100μl enema on the8st day, and3.0mg TNBS/50%ethanol100μl enema on the fifteenth day. DAI was scored for each group, and the mice were terminated on the twenty-first day. The expression of CD98in peripheral blood were measured by flow cytometry. The colon tissues were examined by routine HE and scored for HI. The expression of CD98in the colon was detected by immunohistochemistry.The statistic of results was treated by statistical software SPSS16.0. All the measurement datas were expressed in mean±standard deviation (x±s), and compared the means of samples by single-factor variance analyse,compared all the fourfold table datas by χ2test.We considered test standard a=0.05as the significent test standard.Results1. We found that the colonic mucosal epithelial were intact, the glands were regular in arrangement, and there was almost no inflammatory cell infiltration in the mucosa of the normal control group and saline group. Only a tiny amount of lymphocytes were found in the mucous membrane of the50%ethanol group. We also observed that the epithelium cells were broken, and large amounts of inflammatory cells were infiltrated in the mucosal layer and muscularis,at the same time,there was a piece of necrosis in the mucous membrane and a dermal proliferation of small blood vessels stemming from the muscularis mucosa into the submucosa,and all of them were appeared in the TNBS+50%ethanol group. The worse injury of colonic histological, the higher degree of CD98expression in peripheral blood and colonic mucosal tissue.2. Flow cytometry:all figures were obtained by flow cytometer and two colour fluorescence parameters were analysed by the Cell quest3.0software. The expressions of CD98in the peripheral blood of normal control group, saline group,50%ethanol group and TNBS+50%ethanol group are respectively (71.10±0.81)%,(72.27±1.81)%,(73.72±2.26)%and (81.32±2.87)%, the data differences were statistically significant (F=29.460, P<0.05).The expressions of CD98in the peripheral blood of TNBS+50%ethanol group is higher than other groups.3. Immunohistochemistry:By microscopic examination, scoring was evaluated by the positiveness of cells staining, positive cells counting≤25%:0point;26%-50%:1point;51%-75%:2points;>75%:3points. Scoring was also evaluated by the degree of staining:mild staining counts lpoint, moderate staining counts2points and severe staining counts3points. The positiveness was identified by the sum of the two scores in each slide, it was assumed positive when the scores≥3and negative when the scores<3. The expressions of CD98in intestinal epithelium cells of normal control group, saline group,50%ethanol group and TNBS+50%ethanol group were respectively25.0%(3/12),25.0%(3/12),33.3%(4/12),75.0%(9/12), the data differences were statistically significant (x2=4.567, P<0.05).The expressions of CD98in intestinal epithelium cells of TNBS+50%ethanol group is higher than other groups.Conclusions1.The expressions of CD98on the surface of the peripheral blood cells increase in IBD.2.The expressions of CD98on the surface of the colonic epithelial cells increase in IBD.3.CD98may be important molecules which highly express in the inflammatory bowel disease.4.The expression level of CD98is in line with the severity of colonic inflammation.